Why your payslip differs from a net salary estimate

The reasons a payslip is not the same as an online estimate: tax codes, pensions, benefits, holiday pay, rounding and the year-end settlement.

Updated 17 October 2026

An estimate answers a simpler question

A calculator answers the question "what would a typical employee with this gross salary take home". A payslip answers a different question: what did your employer withhold from you this month, given everything it knows about you. The first can only use public rules, and the second uses your personal data. A difference of a few percent is normal, and a difference of more than ten percent has a cause that you can usually find.

Tax codes, cards and tables

Employers do not choose how much tax to withhold. They follow a code or table from the tax authority. In the UK it is your tax code, 1257L for most people, but a different code can apply if you have a second job, a company car or an unpaid balance from an earlier year. In Norway it is the tax card with its table, and in Sweden the table on your tax decision. In Germany the tax class and the numbers stored in your electronic tax features decide. If the code on your payslip is not the standard one, the estimate will not match.

Pensions, benefits and other deductions

Workplace pension contributions are the most common reason that real net pay is lower than an estimate. A UK employee who pays 5 % into a workplace pension, a Dutch employee who pays a share of the pension fund premium and a Norwegian employee in the public pension scheme all see a deduction that the estimate does not include. Benefits such as a company car, free health insurance or a subsidised phone are taxed as if they were pay and reduce net pay without adding any cash.

Student loan repayments in the UK, union fees in Sweden and Norway and church tax in Germany are other deductions that depend on you and are not part of a standard estimate. Church tax is an option in the German calculator, and the rest are listed on the country pages as not modelled.

Timing, rounding and bonuses

Norwegian employers withhold over 10.5 payslips and give mostly tax-free pay in June, so the regular months are lower than one twelfth of the yearly figure. UK employers calculate tax cumulatively across the year, which makes the first month different from the rest. Dutch employers pay holiday allowance in a separate payment that is taxed on its own. A bonus is often withheld at a higher rate than your normal salary and corrected later.

Rounding adds small differences as well. The German and Swedish rules round at specific steps, and the UK converts the National Insurance thresholds to the length of your pay period. An estimate that uses a yearly figure can differ by a few units a month for this reason alone.

The year-end settlement

Withholding is a prepayment. After the tax year the authority compares what you paid with what you owe. In Sweden, Norway and the Netherlands you check a pre-filled return, in Germany you file an annual return that often leads to a refund, and in the UK the tax code is adjusted automatically or you are asked to complete a self assessment. The estimate shows the tax for a standard year, which is closer to the final settlement than to any single payslip.

Use the estimate to set expectations and your payslip to check them. If one line on your payslip is much larger than in the estimate, look up what it stands for before you raise it with your employer or the tax authority.

Sources

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